Well swab



F. A. THAHELD WELL SWAB Jan. 24, 1939.

2 Sheets-Sheet l Filed April 13, 1936 II .Illll fllzrgifll'i F. A. THAHELD WELL SWAB Jan. 24, 1939.

' 2 Sheets-Sheet 2 Filed April 13, 1936 llllllllll Patented Jan. 24, was

MAW

Guillermo wan. SWAB Dallaa,'1 .udm an. corporatiomD al las,

Tex a corpo- Application April 13, 1936, Serial N0. 74,078

'iClaims.

This invention relates to new and useful im-- movements in well swabs.

One object of the invention ls to provide an improved swab which is particularly adapted for use in swabbing and cleaning well tubing, and the like.

An important object of the invention is to provide an improved well swab which is so constructed that substantially the entire surface of the packing element engages the tubing wall, whereby more eillcient swabbing is had.

Another object of the invention is to provide an improved well swab including an elastic packing element arranged to be distorted into engagement with the tubing or casing wall, with positive means for distorting the lower end of the elastic member after the upper end of said element has engaged the tubing wall, whereby substantially the entire surface of the packing element engages the wall; said means also serving to limit the distortion of the element so as to prevent rupturing or damaging the element under excessive pressure.

A further object of the invention is to provide an improved well swab including an elastic packing member having a floating liner or bushing therein, said liner serving to reinforce and strengthen said packing member.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by'reference to the accompanying drawings, in whichan example of the invention is shown, and wherein:

"Figure 1 is a view, partly in elevation, and partlyin section, of a swab constructed in accordance with the invention and showing the same in its normal position, disengaged from the tubing wall,

Figure 2 is a view, similar to Figure 1, with the swab in its distorted position,

Figure 3 is a horizontal, cross-sectional view, taken on the line 3-3 of, Figure 2,

Figure 4 is a view, partly in elevation'land partly in section of another form of the invention, showing it in its normal disengaged position,

Figure 5 is a view, similar to Figure 4, with the swab distorted,

Figure 6 is a horizontal cross-sectional view, taken on the line 66 of Figure 5,

Figure 7 is a view, similar to Figure 4, of-still another form oi the invention, the swab being in its normal position,

this enlarged portion of the bore and the man- Figure 8 is a view, similar to Figure '7, showing the swab distorted, and

Figure 9 is a horizontal, cross-sectional view, taken on the line 9-9 01 Figure 8.

In the drawings, the numeral l0 designates a tubular mandrel which is provided with an annular oflset or shoulder II. The mandrel may have suitable connection (not shown) at its upper and lower ends. whereby said mandrel may be connected in a string of pipe. An annular thim- 10 ble l2 surrounds the mandrel and rests on the shoulder Ii, whereby it is supported upon the mandrel. The thimble is provided with an annular bevelled upwardly flared recess II which is arranged to receive the lower tapered or conical end ofa packing member H.

' The packing member is constructed of rubber, rubber compound, or other suitable material and has an axial bore IS the lower portion of which is of the same diameter as the outside diameter of the mandrel, whereby it will snugly fit around said mandrel when positioned within the thimble. The upper end of the bore I5 is enlarged at l5 whereby an annular space I! is provided between 5 drel. The extreme upper end of the enlarged portion i5 is flared or curved outwardly so as to assure the entrance of fluid within the annular space H.

An annular metallic bushing or liner i8 is molded, or otherwise secured within the bore ii of the packing member and the upper end portion of this bushing is offset at is whereby an annular flange is formed at the extreme upper end of said bushing. By observing Figure 1, it will be seen that when the bushing is positioned within the bore IS, the oiIset portion is and the flange 20 or said bushing will be embedded within the packing member I. It is noted that the size and location of the bushing is such that the 40 offset portion l9 thereof is positioned -at the lower end of the enlarged portion IQ of the bore, whereby a metallic annular interior shoulder 20' is provided at the lower end of said enlarged portion. It is pointed out that the bushing does not extend normally to the extreme lower end of the packing member H but terminates short thereof whereby when the packing element is in its normal position on the mandrel, there is a goodly portion of the material 01' which the packing member is constructed located between the lower edge of said bushing l8 and the thim- -ble l2.

In operation, the mandrel, and the parts carried thereby, are lowered into the well tubing or casing'A in any suitable manner. The normal position or the packing element II is as shown in Figure 1 with the outer periphery of said packing member retracted from the inner wall of the tubing A. The metallic liner or bushing ID will,

.of course, aid in holding the packing element in this position. Also, while the mandrel is being lowered through the well fluid, said well fluid passing upwardly through the space between the outer periphery of the packing member and the inner surface of the tubing will tend to force the packing element inwardly toward the mandrel. 'l'his annular space also provides a by-pass for the well fluid, whereby the swab may be easily lowered therethrough.

When the upstroke of the swab begins, it will be obvious that the well fluid will enter the annular space I! in the upper end of the packing element i4. Continued upward movement of the mandrel and packing element will cause the pressure of the well fluid to force the upper portion of the packing member ll outwardly into contact with the inner wall of the well tubing A. As soon as this upper portion of the packing member comes into contact with the tubing, the pressure of the well fluid will then be transferred to the metallic member formed by the offset in the bushing 18 and from this point on the pressure of the fluid will be exerted against the lower portion of the packing member M. This pressure will cause the bushing l6 to move downwardly on the mandrel until the lower edge of said bushing contacts the thimble 12 as is shown in Figure 2. During such movement of the bushing IS, the lower portion of the packing member M will be compressed longitudinally and expanded radially outwardly into contact with the tubing because of the offset IS in said bushing, and, thus, it will be seen that the lower portion of the packing member H is moved into engagement with the tubing wall. After the lower edge of the bushing l8 strikes the thimble l2, further movement or distortion of the packing member I4 is prevented and thereafter, regardless of the pressure above the packing member, further distortion connot be had. Thus, it will be seen that the bushing not only serves to distort the lower portion of the packing member into positive engagement with the tubing wall, but also provides a positive means for limiting the distortion of the member beyond its elastic limit. As soon as the pressure is relieved above the packing member It, said member will, of course, immediately move back to its normal position, which is that shown in Figure 1. Upon the next stroke of the swab, the action is repeated.

From the above it will be seen that the metallic bushing not only provides a reinforcement or means for strengthening the elastic packing member l4, but also provides a means for distorting the lower end of the packing member, alter the upper end thereof has moved into engagement with the tubing wall. It is the ofiset in the bushing which assures the distortion of the lower .end of the member II. The bushing further provides a positive stop means, whereby the member l4 cannot be distorted beyond its elastic limit.

In Figures 4 to 6, another form of the invention is shown. In this form, the mandrel Ill having the annular shoulder II is employed, and a suitable thimble is supported on the shoulder H. An elongate elastic packing member 26 has its lower end confined within the thimble .26, while its upper end is confined within a flanged cap 21. The packing member has a bore 28 having the same diameter as the outside diameter of the mandrel Ill, whereby when said member is confined between the cap and thimble, the lower portion of said bore will snugly engage the outer periphery of said mandrel. The upper portion of the bore 26 is enlarged at 28, whereby an elongate annular space or well 30 is formed between the mandrel and packing member. The cap 21 is provided with openings or ports 31 which establish communication between the upper end of the well 30 and the interior of the tubing A. Within the lower end of the packing member 26 an elongate sleeve 32 is molded. The sleeve is positioned similar to the bushing H3 in the first form, and is provided with an outwardly directed annular flange 33 having an annular series of perforations therein and which is, of course, embedded in the packing member 26.

The operation of this form is substantially the same as that of the first herein described form. After the device has been lowered into the well tubing and the upstroke thereof is begun, the well fluid will enter the ports 3| in the cap 21 and flow into the annular space or well 30 in the upper end portion of the packing member 26. The pressure of this fluid will first distort the upper portion of the packing member 26v into engagement with the tubing wall. After such distortion has occurred the pressure of the fluid is then exerted on the lower portion of the packing member 26. The sleeve 32 will act upon the lower portion of the packing member 26 exactly as the bushing l8 acts upon the packing member 14 in the first form, whereby the lower portion of the member 26 is longitudinally compressed and radially distorted into engagement with the tubing. As is clearly shown in Figure 5, when the lower end of the sleeve 32 strikes the thimble 25, further distortion of the packing member 26 is prevented.

In Figures 7 to 9, I have shown still another form of the invention. This form is very similar to that shown in Figures 1 to 3 and includes a mandrel I0 having the shoulder II. A thimble i2 similar to the thimble i2 is supported on the shoulder II. The lower end of a packing member I4 is supported within the thimble. The structure of the packing member I4 is very similar to the structure of the member H except that it is slightly longer in proportion to the diameter. A bushing I8 is molded within the member l4, and an annular well or space I1 is provided within the upper portion of the member H. The only material difierence between the form shown in Figure 1 and this last described form is that the packing member I4 is confined within a vertical cage 40, said cage including a plurality of rods 4| which engage in longitudinal grooves 42 provided in the outer periphery of the member H. The cage serves to reinforce and further brace the packing member H. The operation of this form, however, is exactly the same as that of the form shown in Figures 1 to 3 as to the initial engagement of the upper portion of the packing member l4 and subsequent engagement of its lower portion with the well tubing or casing A.

What I claim and desire to secure by Letters Patent, is:

1. A well swab including, a support, an elastic packing member carried by the support, the upper portion of said member being annularly vent the distortion of cupped whereby it may be expanded into packing position by the pressure of the well fluid thereabove, means for longitudinally compressing and radially expanding the lower portion of said member into packing position under pressure of the well fluid after engagement of the upper portion of the packing member with the well tubing, and means for preventing the distortion of said member beyond its elastic limit in operation.

2. A well swab including, a support, an elastic packing member carried by the support, a metallic liner bushing molded within the packing member for reinforcing the same, the upper portion of the packing member being annularly cupped whereby it may be expanded into packing position by the pressure of the well fluid thereabove, said liner bushing being movable longitudinally on the support and acting to longitudinally compress and radially expand the lower portion of the packing member into packing position under pressure of the well fluid thereabove after expansion of the upper portion of the packing member, and means for limiting the longitudinal movement of said liner bushing whereby the distortion of the packing member beyond its elastic limit is prevented.

3. A well swab including, a support, an elastic packing member carried by the support and having an annular open space in its upper portion whereby the well fluid entering said space under pressure from above will distort and radially expand the upper portion of the member into packing contact with the well tubing, a liner bushing slidably fitted on said support and having an outwardly oiTset annular upper end portion embedded in said packing member for distorting the lower portion of said packing member and expanding it into packing contact with the well tubing, and means for limiting the endwise movement of said liner bushing whereby to prethe packing member beyond its elastic limit.

4. A well swab including, a mandrel, an annular thimble sleeved and supported on said mandrel, a tubular elastic packing member sleeved on said mandrel and having its lower end portion supported in the thimble, said packing member having an annular open space in its upper portion whereby fluid may enter said space to expand the upper portion of said member, and a metallic liner bushing slidably fltted on said 6. A well swab including, a mandrel, a tubular elastic packing member sleeved on the mandrel, the memberhaving an upper bore portion of a greater diameter than the lower end portion aifording an annular fluid receiving chamber, a liner bushing in the lower portion of said packing member and slidably fitted on said mandrel, the upper end portion of the bushing being located at the bottom of said fluid receiving chamber and being formed with an outwardly ofiset annular portion which is embedded in the packing member, and an annular thimble sleeved and supported on said mandrel to receive and support the reduced lower end portion of said packing member.

7. A well swab including, a mandrel, a tubu- -lar elastic packing member sleeved on the mandrel, the member having an upper bore portion of a greater diameter than the lower end portion ailording an annular fluid receiving cham ber, 'a liner bushing in the lower portion of said packing member and slidably fitted on said man drel, the upper end portion of the bushing being located at the bottom of said fluid receiving chamber and being formed with an outwardly offset annular portion embedded in the packing -member, an annularly cupped thimble sleeved and supported on said mandrel to receive and support the reduced lower end portion of said packing member, and an inverted annularly cupped thimble sleeved slidably on said mandrel in opposed relation to said supported lower thimble to flt over the reduced upper end portion of the packing member, said upper thimble having openings therein to admit well fluid from above to the fluid receiving chamber of the packing member. I

' PERI A. 'I'HAHELD. 

